Turret assembly



Oct. 17, 1961 J; H. ADAMSHECK ETAL TURRET ASSEMBLY Filed Feb. 26, 1958To OSCILLATOR Gnecut 'r M 0 w WWW a o I 5 2 MW a a 3 JWm A 2 m 6 3 w 3JR a U ited st Pm 3,005,115 TURRET ASSEMBLY James H. Adamsheck,Hiawatha, and Robert .I. Rowley, Cedar Rapids, Iowa, assignors toCollins Radio Com- 'pany, Cedar Rapids, Iowa, a corporation of IowaFiled Feb. 26, 1958, Ser. No. 717,781

6 Claims. (Cl. 3071-156) capacitance is feasible. In more compactconstructions,

such as a turret assembly of plugged-in crystals covered by an ovenassembly, the compensating inductances become a very difficult problem;first, in making them small enough and, second, in placing them so thatthey are compactly arrayed.

Accordingly, it is an object of the invention to provide a crystalturret assembly having compactly arrayed shunting inductances for eachof the crystals so mounted.

It is a further object of this invention to provide the functions ofswitch contact, crystal connector and mounting, and shunting coil insimplified organization.

It is a feature of this invention to provide a connective conductivemember comprising a switch contact, a coil form, and a pin receptacle ina single unit and providing a compactness at least equal to thecompactness of the piezoelectric crystal mounted therewith.

Further objects, features, and advantages of the invention will becomeapparent from the following description and claims when read inconjunction with the drawings, in which:

FIGURE 1 shows a sectioned isometric view of the invention incorporatedin a crystal turret oven assembly; and

FIGURE 2 shows a section of a conductor used in FIGURE 1.

In FIGURE 1 a crystal turret 10 is mounted for rotation on a shaft 11.The turret comprises a plurality of crystals 12 mounted on thecircumference of a circle. These crystals are piezoelectric devicesmounted within a metallic shield can and having two relatively rigidpins extending from one end. These pins comprise the electrical circuitconnections for the crystal and also serve as mechanical mounting means.The oven assembly comprises a heater coil 14 wrapped around a metallicshield or can 15. Thermostat 16 is mounted on can 15 centrally of thecrystals. A disc 17 of thermal insulation material is mountedon the endof the can 15 to reduce thermal losses.

The other end of the turret is constructed around an insulating block 20which is mounted on shaft 11. An insulating plate 21 is fastened toblock 20 and serves as a holder for one end of the conductors orconnective members which perform several services as enumerated below.The other ends of the conductors 25 are held by a second insulatingplate 22 mounted on the end of block 20 opposite plate 21. Can 15 isfastened to block 20 by means of screws and studs, 23 and 24,respectively.

Shaft 11 is mounted in bearings which permit rotation but providedefinite positioning longitudinally. Indexing means and means forrotating the shaft also are provided, as are well known in the art.Similarly, wiper contacts 19, mounted in an insulating block 18, areprovided for making the circuit connection between an external circuit,

3,005,1 15 Patented Oct. 17, 1961 ice such as an oscillator circuit, andthe particular crystal selected by the rotation and indexing of theturret. Plate 13 provides meansfor a wiper ground connection to the ovenwhile another plate, not illustrated, is used to transfer heatingcurrent to the heater coil 14.

. As may be readily seen, crystal conductors 25 accept the pins of thecrystals in one end 26 and conduct crystal currents through to theswitch formed by wiper contact 19 at the other end 27. A shuntinginductance 28 is provided which is used to neutralize the electrodecapacitance of the crystal. One end of the coil 28 is connected, such asby soldering, directlyto conductor 25 mounting the coil. The other endof the coil is brought over to the second conductor, similarto conductor25 except for the coiland coil form, and connected thereto.

InFIGURE 2, conductor .25 has a pin receiving end I 26 and a roundedswitch contact end 27. Recess 30, which provides for the accommodationof a crystal pin, is large enough to accommodate a spring 31.; Spring 31provides a firm electrical contact and mechanical support.

' Mounted on, and concentric with conductor 25, is an insu lating coilform32. Form 32 is a spooLshaped form having the length and height offlange needed to carry the required coil 28. Slots such as 33 areprovided in the flanges for holding the ends of the coil.

While the size of the recess 30 in the pin receiving end 26 is dictatedby the size of the pin, and the rounded opposite end 27 is made largeenough to provide reliable switching characteristics, the length of theconductor 25 may be any length greater than that necessary toaccommodate the contact spring 31 or coil form 32, whichever is longer.Conductor 25 is provided with shoulders 34 and 35 which serve to containthe conductor between the mounting plates 21 and 22. A further shoulder36 serves to retain coil form 32 against plate 21.

In operation or use of the device, the turret is assembled, the crystals12 are plugged in and the oven cap is assembled over the crystals toheat them and to retain them. Inductance coil 28 is then adjusted asnecessary to provide the necessary neutralizing of the electrodecapacity of the crystals. The ends of the coil 28 are connected to itspair of conductors in the final assembly, providing the shuntinginductance needed.

Rotation of the turret assembly by shaft 11 positions one pair of theconductors 25 under the wiper contacts 19 for circuit connection to thedesired crystal. Because the inductances are adjusted for each crystal,the terminals provided by wiper contacts 19 provide a fully compensatedswitched crystal circuit.

Although this invention has been described with respect to a particularembodiment thereof, it is not to be so limited because changes andmodifications may be made therein which are within the full intendedscope of the invention as defined by the appended claims.

What is claimed is: i 1. A selective switching means comprising ahousing and at least a pair of wiping contacts, said housing and wipingcontacts arranged to move with respect to each other, said housingincluding a plurality of circuit components and a plurality ofconnective members con structed and arranged to connect individual onesof said circuit components to said wiping contacts as said housing andwiping contacts are moved with respect to each other, each of saidconnective members comprising a conductive member having a pin-receivingaperture in a first end thereof, an insulated coil form mounted on saidconnective member, coil means having two terminals and being wound onsaid coil form, one of the terminals of said coil means beingelectrically connected to one of said wiping contacts and the otherterminal of said coil means being electrically connected to anotherwiping contact.

2. A selective switching means in accordance with claim 1, comprising arotatable shaft and in which said housing comprises a turret-likestructure mounted upon said rotatable shaft, and in which the said otherends of said connective members and said wiping contacts are sopositioned with respect to eachother that at least one of said wipingcontacts will make with the other ends of successive ones of saidconnective members as said turret-like structure is rotated.

3. A selective switching means in accordance with claim 1 in which saidhousing comprises a turret-like structure and in which said connectiveelements and said wiping contacts are so positioned with respect to eachother that at least one of said wiping contacts will make with the saidother ends of successive ones of said connective members as saidturret-like structure and said- Wiping contacts are moved with respectto each other.

4. A selective switching means in accordance with claim 3, comprisingspring means arranged Within said pin-receiving aperture for firmlyholding and for providing good electrical contact with a pin inserted insaid aperture.

5. In a selective switching means comprising a housing and a pluralityof wiping contacts, said housing and wiping contacts arranged to movewith respect to each other, said housing including at least one circuitcomponent, at

least one connective member constructed and arranged to connect saidcircuit component to one of said wiping contacts as said housing andwiping contacts are moved with respect to each other, said connectivemember comprising stray capacitance, said connective member furthercomprising a conductive member having a pin-receiving aperture in oneend thereof, an insulated coil form mounted on said conductor, saidconnective member coil means constructed and arranged to compensate forsaid stray capacitance, said coil means having two terminals and beingwound on said coil form, one of the terminals of said coil means beingelectrically connected to one of said wiping contacts and the otherterminal of said coil means being electrically connected to anotherwiping contact.

6. A selective switching means in accordance with Murdock Aug. 23, 1932'McCarthy Dec. 11, 1956"

